What makes it different
The gap
Section titled “The gap”Signing documents electronically in Portugal used to mean choosing between two bad options.
On one side, the international e-signature tools: easy to use, but what they produce is almost always a simple signature — a visual stamp and a record that somebody clicked. They sell “legal validity” without explaining that this validity is left to a court’s free assessment.
On the other, the traditional qualified route: a digital certificate bought from a provider, a card reader, software to install. Legally solid, and impractical if you want a client to sign a contract this afternoon.
AssinaJá starts from a simple observation: Portuguese citizens already hold a qualified electronic identity — Chave Móvel Digital — and need buy nothing to use it. What was missing was a platform that integrated it with the usability of the generic tools.
What it does differently
Section titled “What it does differently”Each point below is an implemented behaviour, not an intention.
Sealed before anyone signs
Section titled “Sealed before anyone signs”AssinaJá applies a certifying seal to the document at the moment it is sent, before the first signer touches it — except when the PDF arrives with signatures already inside, which carries no seal. The seal blocks changes to page content, permitting only field filling, additional signatures and annotations.
The consequence is counter-intuitive: even a document signed only with a simple visual signature leaves the platform as a cryptographically sealed PDF, with a qualified timestamp and integrity verification. The details, and the exception, are in The certification seal.
Qualified signatures with the national eID
Section titled “Qualified signatures with the national eID”The AMA integration allows signing with Chave Móvel Digital without a purchased certificate, without a card reader, and without installing anything — just a phone and the signing PIN.
The result is validated by independent tools as a qualified signature, with legal equivalence to a handwritten signature across the EU. See Qualified signatures with CMD.
Proof of professional capacity, not only identity
Section titled “Proof of professional capacity, not only identity”With professional attributes (SCAP), the document gains signatures from the certifying bodies themselves, attesting the capacity in which the signer signed. An opinion signed by a lawyer no longer rests on the claim that they are one. See CMD and CMD with Professional Attributes.
A chained audit trail
Section titled “A chained audit trail”Every event on a document is tied to the previous one by a SHA-256 hash, and the chain is recomputed when the Completion Report is generated: altering or removing a record stops it matching. See How the history is chained.
Verifiable without AssinaJá
Section titled “Verifiable without AssinaJá”Signed documents verify in Adobe Reader or the European Commission’s validator, using only what is embedded in the file. The platform does not need to be reachable, nor the company to exist.
Worth spelling out what that implies: whoever signs is not dependent on us to prove they signed.
Documents in the customer’s own storage
Section titled “Documents in the customer’s own storage”Organisations that require it can connect their own Azure Blob Storage account. Documents then live in the customer’s tenant rather than the platform’s shared storage.
Built for AI assistants
Section titled “Built for AI assistants”AssinaJá exposes an official MCP server, with scope-based authorisation and consent recorded as auditable evidence. An assistant can prepare documents without ever touching the user’s account, and cannot send them unless granted that permission.
The policy that makes AI-created documents start as drafts is what makes this usable without anxiety — see Configure organisation policies.
Cross-organisation template catalogue
Section titled “Cross-organisation template catalogue”One organisation can make its templates available for others to generate documents from, while each document, signing process and billing stays with the organisation that generated it.
In short
Section titled “In short”What sets AssinaJá apart is not doing the same thing faster. It is that the strongest signature Portuguese law recognises — the qualified one, equivalent to a handwritten signature — stops requiring equipment, purchases or installations, and comes within reach of anyone with a phone and an activated Chave Móvel Digital.
And because that is a large claim, the site also states where the limits are.